1. Field of the Invention
This invention is related to and has among its objects the provision of novel mushroom-growing media and novel methods of making the same. It is a particular object of the invention to provide media or compost for growing mushrooms that is ready for spawning within one day from the start of its preparation. Further objects of the invention will be evident from the following description wherein parts and percentages are by weight unless otherwise specified.
2. Description of the Prior Art
In the commercial production of mushrooms compost material usually is employed as a medium for growth. After formation of the compost, it is treated so that the microoganisms present are stimulated to make the compost suitable for the growth of mushrooms. Classically, composting material, e.g., horse manure, straw, or other suitable substitute, is assemnbled into piles and wetted. It is also a general practice to incorporate supplements such as nitrogen sources, minerals, and vitamins into the cellulosic compost. Then, the mixture is turned to aerate it three to four times during the next 7 to 10 days. During the entire process rapid, aerobic, thermophilic, microbial activity occurs and the temperature of the compost rises to about 55.degree. to 80.degree. C.
After initial composting is completed, the compost material is formed into beds in an enclosed space, usually indoors, and is allowed to ferment for another day or two. Then, steam and ventilation are introduced into the cellulosic material to raise the ambient temperature to about 60.degree.-70.degree. C. for about 6 hours. The temperature is allowed to fall to about 52.degree. C. over the next 5 to 9 days. After further cooling, the compost is ready to be spawned with either solid or liquid spawn of the variety of mushroom to be cultivated.
Control of the aforementioned compost preparation is difficult and often oxygen is consumed so rapdily that anerobic metabolism occurs. Metabolites manufactured during anaerobic growth are detrimental to mushroom growth and must be avoided.
A summary of conventional approaches to compost preparation is found in "Composting" by W. A. Hayes, published by W. S. Maney and Son, Ltd., Leeds, England (1977).
Submerged propagation has been suggested for the production of liquid mushroom mycelium spawn (Humfeld et al., Food Technology, 1949, Vol. 3, No. 11, pages 355-356; Block et al., Agricultural And Food Chemistry, 1953, Vol. 1, No. 14, pages 890-893; Szuecs, U.S. Pat. No. 2,505,811; and Laniece et al., U.S. Pat. No. 3,286,399). In submerged culture of liquid mushroom mycelium spawn, a liquid medium is prepared from, for example, asparagusbutt juice, pear-waste juice, grain extract such as rice bran extract, synthetic media containing suitable carbohydrates, nitorgen sources, and inorganic salts, and so forth. The liquid medium is sterilized and inoculated with previously prepared growing mycelium culture. The mixture is fermented for about 4 to 7 days during which time mycelium growth is substantially completed. The so-prepared liquid medium is used to "spawn" solid compost material prepared for growing mushrooms.
The known method of mushroom production using a solid compost material is time-consuming because it requires at least two weeks to prepare the solid compost for spawning.
In U.S. Pat. No. 4,127,965, Mee discloses composting compositions which avoid conventional composting for production of mushrooms requiring casing. Cold manure is combined with a naturally occurring humic acid containing colloidal material and a small amount of inorganic material to enhance permeability. Upon addition of water to and pasteurization of this combination, it is found that the nitrogen content of the composition is substantially maintained and there is a substantial absence of free ammonia. The composting is inoculated then with spawn and incubated, and a casing is applied to the composting. The procedure for growing and harvesting mushrooms is conventional.